Bronchiolitis obliterans
Rare lung disease causing airway obstruction from inflammation and scarring.
Bronchiolitis obliterans, also called obliterative bronchiolitis, constrictive bronchiolitis, or popcorn lung, is a condition where the smallest airways in the lungs become blocked due to inflammation. People with this disease typically experience a dry cough, shortness of breath, wheezing, and fatigue, and these symptoms tend to get worse over a period of weeks to months. It is a separate condition from cryptogenic organizing pneumonia, which was once known as bronchiolitis obliterans organizing pneumonia.
The disease can be triggered by inhaling toxic fumes, respiratory infections, connective tissue disorders, or complications after a bone marrow or heart-lung transplant. Symptoms may not appear until two to eight weeks after exposure to toxins or infection. The underlying problem is inflammation that leads to scar tissue forming in the airways. Doctors diagnose it using CT scans, pulmonary function tests, or a lung biopsy; a chest X-ray often looks normal.
Although the damage is not reversible, treatments can help slow the progression. These may include corticosteroids or immunosuppressive drugs. In some cases, a lung transplant is an option. The outlook is generally poor, with many people surviving only months to years after diagnosis.
Bronchiolitis obliterans is rare in the general population. However, it affects about 75% of people within ten years of a lung transplant and up to 10% of those who have received a bone marrow transplant from another person. The condition was first clearly described in 1981, though earlier descriptions date back to 1956, and the term "bronchiolitis obliterans" was first used by Reynaud in 1835.
Signs and symptoms include worsening shortness of breath, wheezing, and a dry cough. These may start gradually or come on suddenly. The symptoms reflect an obstructive pattern that does not improve with bronchodilator therapy and must be linked to a prior lung insult, such as inhalation injury, post-transplant autoimmune injury, infection, drug reactions, or autoimmune diseases.
Many factors can cause bronchiolitis obliterans. These include collagen vascular disease, transplant rejection, viral infections (such as adenovirus, respiratory syncytial virus, influenza, HIV, and cytomegalovirus), Stevens-Johnson syndrome, Pneumocystis pneumonia, drug reactions, aspiration, complications of prematurity, and exposure to toxic fumes. S
- field
- Respiratory disease
- known_for
- Obstruction of small airways due to inflammation, also called popcorn lung
- first_clearly_described
- 1981
- earlier_term_used
- 1835 by Reynaud
- affects_after_lung_transplant
- About 75% by ten years
- affects_after_bone_marrow_transplant
- Up to 10%
Lore & Background
Bronchiolitis obliterans has many possible causes, including collagen vascular disease, transplant rejection in organ transplant patients, viral infection (adenovirus, respiratory syncytial virus, influenza, HIV, cytomegalovirus), Stevens–Johnson syndrome, Pneumocystis pneumonia, drug reaction, aspiration and complications of prematurity (bronchopulmonary dysplasia), and exposure to toxic fumes. Toxins implicated include diacetyl, sulfur dioxide, nitrogen dioxide, ammonia, chlorine, thionyl chloride, methyl isocyanate, hydrogen fluoride, hydrogen bromide, hydrogen chloride, hydrogen sulfide, phosgene, polyamide-amine dyes, mustard gas and ozone. It can also be present in patients with IBD, systemic lupus erythematosus, juvenile idiopathic arthritis, rheumatoid arthritis, GERD, IgA nephropathy, and ataxia telangiectasia. Activated charcoal has been known to cause it when aspirated. The ingestion of large doses of papaverine in the vegetable Sauropus androgynus has caused it. Additionally, the disorder may be idiopathic.
Reader's Guide
Bronchiolitis obliterans is a rare but serious lung disease characterized by inflammation and scarring of the smallest airways, leading to progressive obstruction. Its significance lies in its association with a wide range of triggers, from toxic fume exposure (notably diacetyl in microwave popcorn production, giving it the name 'popcorn lung') to post-transplant complications and viral infections. The disease is particularly impactful in lung transplant recipients, affecting about 75% of people by ten years following transplant, and up to 10% of bone marrow transplant recipients. Diagnosis often requires CT scan, pulmonary function tests, or lung biopsy, as chest X-rays are frequently normal. While not reversible, treatments such as corticosteroids or immunosuppressive medication can slow worsening, and lung transplant may be offered. Outcomes are often poor, with most people dying in months to years. The condition was first clearly described in 1981, though earlier descriptions date to 1956 and the term 'bronchiolitis obliterans' was used by Reynaud in 1835. Its legacy includes ongoing research into post-infectious cases in children, particularly in South America, and emerging concerns about burn pit exposure in veterans.
Did You Know?
- Bronchiolitis obliterans is also known as popcorn lung due to its association with diacetyl, a chemical used in artificial butter flavoring for microwave popcorn.
- The condition was first clearly described in 1981, though the term 'bronchiolitis obliterans' was used by Reynaud in 1835.
- It affects about 75% of people by ten years following a lung transplant and up to 10% of people who have received a bone marrow transplant from someone else.
- Post-infectious bronchiolitis obliterans is most common in the southern hemisphere, particularly in Brazil, Argentina, Australia, Chile and New Zealand.
Frequently Asked Questions
Who is Bronchiolitis obliterans?
Bronchiolitis obliterans is a rare respiratory condition in which the tiniest airways of the lungs become narrowed or sealed off by chronic inflammation and scar tissue. It goes by several aliases in medical literature, including obliterative bronchiolitis, constrictive bronchiolitis, and the colloquial nickname 'popcorn lung.'
What are Bronchiolitis obliterans's powers/role?
Its signature effect is progressive obstruction of the small airways, producing a dry cough, worsening shortness of breath, wheezing, and fatigue that typically escalate over several weeks to months. It is a distinct entity from cryptogenic organizing pneumonia, a condition that was once mistakenly lumped under the same name.
How does Bronchiolitis obliterans's story end?
Because the damage involves irreversible scarring of the small airways, there is currently no treatment that can fully reverse the obstruction once established. Management focuses on slowing progression with immunosuppressive or anti-inflammatory medications, but the condition generally follows a slow, worsening course.
Why is Bronchiolitis obliterans important?
It is a leading long-term complication after organ transplantation, affecting roughly 75 percent of lung-transplant recipients within ten years and up to 10 percent of bone-marrow-transplant patients. It can also be triggered by inhaling toxic fumes, certain respiratory infections, or connective-tissue disorders.
Where did Bronchiolitis obliterans first appear?
The condition was first clearly described in the modern medical literature in 1981, though an earlier related term was used by the French physician Reynaud as far back as 1835. Its formal recognition as a distinct entity separate from organizing pneumonia came even later.
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